Bloodstream infections in the era of the COVID-19 pandemic: Changing epidemiology of antimicrobial resistance in the intensive care unit

The Coronavirus disease 2019 (COVID-19) pandemic increased the burden of critically ill patients who required hospitalization in the intensive care unit (ICU). Bacterial and fungal co-infections, including bloodstream infections (BSIs), increased significantly in ICU patients with COVID-19; this had a significant negative impact on patient outcomes. Reported data pertaining to BSI episodes from the ICU setting during the COVID-19 pandemic were collected and analyzed for this narrative review. We searched the PubMed database for articles published between March 2020 and October 2023; the terms "COVID-19 " AND "bloodstream infections " AND "ICU " were used for the search. A total of 778 articles were retrieved; however, only 27 were exclusively related to BSIs in ICU patients with COVID-19. Data pertaining to the epidemiological characteristics, risk factors, characteristics of bacterial and fungal BSIs, patterns of antimicrobial resistance, and comparisons between ICU and nonICU patients during and before the COVID-19 pandemic were obtained. Data on antimicrobial stewardship and infection-control policies were also included. The rates of BSI were found to have increased among ICU patients with COVID-19 than in non-COVID-19 patients and those admitted during the pre-pandemic period. Male gender, 60-70 years of age, increased body mass index, high Sequential Organ Failure Assessment scores at admission, prolonged hospital and ICU stay, use of central lines, invasive ventilation, and receipt of extracorporeal membrane oxygenation were all defined as risk factors for BSI. The use of immune modulators for COVID-19 appeared to increase the risk of BSI; however, the available data are conflicting. Overall, Enterococci, Acinetobacter baumannii , and Candida spp. emerged as prominent infecting organisms during the pandemic; along with Enterobacterales and Pseudomonas aeruginosa they had a significant impact on mortality. Multidrug-resistant organisms prevailed in the ICU, especially if antimicrobial resistance was established before the COVID-19 pandemic and were significantly associated with increased mortality rates. The unnecessary and widespread use of antibiotics further increased the prevalence of multidrug-resistant organisms during COVID-19. Notably, the data indicated a significant increase in contaminants in blood cultures; this highlighted the decline in compliance with infection-control measures, especially during the initial waves of the pandemic. The implementation of infection-control policies along with antibiotic stewardship succeeded in significantly reducing the rates of blood contamination and BSI pathogens. BSIs considerably worsened outcomes in patients with COVID-19 who were admitted to ICUs. Further studies are needed to evaluate adequate preventive and control measures that may increase preparedness for the future.